The sky appears lighter (paler in color) at the horizon because of increased light scattering.
The Science Behind It
As you look towards the horizon, the light from the sun has to travel through a greater amount of atmosphere to reach your eyes. According to the provided reference, "To reach you, the scattered blue light must pass through more air."
Increased Scattering
- Longer Path Length: The longer path length through the atmosphere means more air molecules, dust, and other particles are in the way.
- More Scattering Occurs: This increased density of particles leads to more scattering of the blue light. "Some of it gets scattered away again in other directions."
- Less Blue Light Reaches Your Eyes: Because blue light is scattered away multiple times, less of it reaches your eye directly.
What You See
As the blue light is scattered away, the light that finally reaches your eyes is composed of other colors, such as white and yellow, making the horizon appear paler.
Visualizing the Concept
| Feature | Description |
|---|---|
| Path Length | Longer at the horizon compared to directly overhead. |
| Scattering | Higher scattering rate due to increased atmospheric particles. |
| Light Observed | More white/yellow light, less blue, resulting in a paler appearance. |
